老人代步车卖掉牌照的处理方法是,先到车管所提出注销手续,办理完注销后将车牌交回车管所,并缴纳相应的注销费用。-sales,This process is generally the same in different regions of China, but the specific cost and process may vary slightly, so it is advisable to consult the local traffic management department for specific details.